1. Field of the Invention
This invention relates to milk line systems and especially to protective guards for isolating milk valves from contamination by their surroundings.
2. Discussion of Related Art
Low pipeline installations have become popular in elevated milking parlors for some time, but are a new idea in born tie stall. The purpose of installing the pipeline at a low level is to prevent vacuum fluctuations at the teat end. When there is excessive fluctuation at the teat end, the cow is more susceptible to infections of mastitis due to tissue damage.
Pipelines in tie stall barns have traditionally been high line installations having a height of from five to seven feet or higher. Installations such as these can cause severe fluctuations on the column as milk drops back in the milk hose between pulsations.
Many valves for use in milk lines have been suggested. However, none provides adequate protection from contamination or damage when used in a low line installation. For instance, U.S. Pat. No. 3,967,810, issued July 6, 1976, to Pulvermacher, shows a pipeline inlet valve having a valve housing to receive an inlet pipe. A spring biased cover moves under force of a spring to a closed position to seal the inlet pipe opening when not in use. The cover also carries a neoprene rubber seal to seal the opening. When the inlet pipe is inserted in place, the cover is displaced and a concave recess in the covering engages the inlet pipe and secures the pipe in place and provides a fluid seal. U.S. Pat. No. 3,480,252, issued Nov. 25, 1969, to Simons, shows a pipeline milking system which includes a valve body mounted on a pipeline and having an opening in alignment with an opening in the pipeline. The opening in the valve body is enclosed by a hinged lid. U.S. Pat. No. 3,055,385, issued Sept. 25, 1962, to Tieken, shows a milk pipeline valve having a nipple at a valve with a member carried in the nipple between the nipple ends. A removable closure has a position in sealed engagement with the open end of the nipple and a recessed guard for the closure is carried by a strap surrounding the nipple. The closure is mounted on the strap by a spring connected therebetween. The closure is movable between a position in sealed engagement with the open end of the nipple and a position with the sealing surface received in the recess of the guard. U.S. Pat. No. 3,872,882, issued Mar. 25, 1975, to Fjermestad et al, shows a milk line nipple protector having a flexible resilient sleeve member with transverse corrugations secured to the milk line nipple at its inner end and in telescoping encasing relationship and having a rigid ring member at its outer end mounted in sliding relation to the nipple. The sleeve is compressible relative to the nipple to permit ready attachment of the milking machine connector to the nipple and automatically returns to contamination protective encasing relation to the nipple upon withdrawal of the milking machine connector.